This application relates generally to contrast agents for diagnostic imaging, such as for use in X-ray/Computed Tomography (CT) or Magnetic Resonance Imaging (MRI). More particularly, the application relates to nanoparticle-based contrast agents, and methods for making and using such agents.
Iodinated aromatic compounds serve as standard X-ray/computed tomography (CT) contrast agents. Similarly, gadolinium chelates are the most commonly used contrast agents for Magnetic Resonance Imaging. Such standard contrast agents are typically of low molecular weight, and they are known to have disadvantages such as rapid clearance, leakage through blood vessel walls, lower sensitivity, high viscosity, high osmolality and toxicity. In the case of contrast agents, it is preferred to have maximum renal clearance of the agents from the body without causing short term or long term toxicity to any organs. Thus there is a need for a new class of contrast agents.
Nanoparticles are being widely studied for uses in medical applications, both diagnostic and therapeutic. While only a few nanoparticle-based agents are clinically approved for magnetic resonance imaging applications and for drug delivery applications, hundreds of such agents are still in development. There is substantial evidence that nanoparticles have benefits over currently used standard contrast agents in terms of efficacy for diagnostics and therapeutics. However, the effects of particle size, structure, and surface properties on the in-vivo bio-distribution and clearance of nanoparticle agents are not well understood.
In view of the above, there is a need for nanoparticle-based contrast agents with improved properties having high renal clearance and low toxicity.